Non-rotating rope with spiral strands

ABSTRACT

The present rope is torsion free mainly because it has an inner rope formed by an inner layer of strands which is surrounded by an outer layer of strands and since the inner rope is constructed of at least three flattened strands and at least three round strands which are smaller than the flattened strands to fill the spacings between adjacent flattened strands. The inner strands surround a center member of elastic material.

Muted States Patent 1191 1111 3,729,921 Stroh 1 1 May 1, 1973 4] NON-ROTATING ROPE WITH SPIRAL 2,162,130 6/1939 Somerville ..s7/14s STRANDS I FOREIGN PATENTS OR APPLICATIONS [75] Inventor: Bernhard Stroh, Wren, Austria 1,588 l/l9l0 Great Britain ..57/l45 [73] Assrgnee: Cordeurop Establishment, Vaduz,

Liechtenstein OTHER PUBLICATIONS 1221 Filed: pr- 22. 1 71' German Publication N0. 1,003,097, February 1957, 21 Appl. No.2 136,387 Hans F Primary Examiner-Donald E. Watkins [30] Foreign Application Priority Data Attorney-W. G. Fasse A r. 27, 1970 A 1' .3804

p 1 57 ABSTRACT US. Cl. The present rope is torsion free mainly because has CL 6 1 ..D07b an inner rope formed an inner layer of strands [58] Fleld of Search ..57/l39, I44, 145, which i Surrounded by an outer layer f Strands d 57/146 1631 91 15 since the inner rope is constructed of at least three flattened strands and at least three round strands [56] References cued which are smaller than the flattened strands to fill the UNITED STATES PATENTS spacings between adjacent flattened strands. The inner strands surround a center member of elastic material. 3,457,718 7/1969 Otto et al. ..57/l6l 2,098,163 11/1937 Reed ..57/145 X 14 Claims, 3 Drawing Figures BACKGROUND OF THE INVENTION The present invention relates to torsion free ropes made of spiral or helical strands. More specifically, the present invention relates to two layer ropes in which the layers have opposite directions of lay.

Multilayer ropes are known in the art which are substantially torsion free or non-rotating. These multilayer ropes, especially, if they are manufactured with a so called lang lay in which the wires in the strand and the strands themselves are laid in the same direction, have a high durability because this type of lay assures a good contact between the rope and the sheave groove. However, even these multilayer prior art ropes are subject to excessive wear and tear, especially if the rope is pinched at the bottom of the groove.

OBJECTS OF THE INVENTION In view of the foregoing, it is the aim of the invention to achieve the following objects singly or in combination:

to combine the high durability of non-rotating multilayer ropes with the ruggedness of flattened strand ropes; to construct a multilayer, especially a two layer rope in such a manner that the metallic cross sectional area of an inner or central rope is substantially larger than the metallic cross sectional area of the outer layer of strands, whereby the rope becomes non-rotating, to combine the two layers of strands of a rope which may also be referred to as an inner rope and an outer rope in such a manner that the rotating moments resulting from load conditions in the individual layers of strands compensate each other;

to increase the metallic cross sectional area of the inner rope by providing so called filler strands, preferably without any fiber or synthetic material core; and

to provide a method fo'r flattening round rope strands by subjecting these round rope strands to pressure.

SUMMARY OF THE INVENTION The above objects have been achieved according to the invention in a torsion free rope comprising two layers of strands one of which forms an inner rope and the other of which surrounds said inner rope, whereby the inner rope comprises three to six, preferably three, flattened strands having an elastic strand core and three to six, preferably three, thinner strands, preferably of wires and wherein the inner rope strands are arranged around a common center member. The common center member as well as the elastic strand cores of the flattened strands may be made of natural fiber material or of synthetic fiber material or even of synthetic material wire. Thus, the inner rope of the spiral strand rope according to the invention is formed to comprise six to twelve, preferably six, strands and a thin central member made of fiber or synthetic materi' al.

SHORT FIGURE DESCRIPTION In order that the invention may be clearly understood, it will now be described, by way of example, with reference to the accompanying drawings wherein:

FIG. 1 shows an end view of a rope constructed according to the invention; and

FIGS. 2 and 3 illustrate modifications of the embodiment ofFIG. 1.

DESCRIPTION OF EXAMPLE EMBODIMENT The sectional view of FIG. 1 illustrates a two layer rope. The inner layer of strands forms a so called inner rope A which is surrounded by an outer layer B of outer strands. The inner rope or layer of strands comprises, for example, three flattened strands 2 and three filler strands 6 which are arranged to surround a thin elastic center member 1. For claritys sake the tiller strands 6 are shown slightly out of contact with the flattened strands 2. In the actual embodiment, there will be a close contact between the flattened strands 2 and the filler strands 6 forming said inner rope A.

It will be noted that the flattened strands 2 have a substantially larger dimension than the tiller strands 6. Moreover, each of the flattened strands 2 comprises its own strand core 3 of elastic material. Preferably, the flattened strands 2 are constructed to comprise a double layer of strand forming means such as wire, arranged in a so called parallel or equal lay assembly wherein the wires do not overlap or cut across each other in any given strand and wherein the wires have the same length of lay but different direction of lay. The first or inner layer of the strands 2 comprises strand forming material such as wire of uniform diameter, whereas, in the shown example, the second or outer layer comprises wires of different diameters arranged in such a manner that wires 4 of smaller diameter alternate with wires 5 having a larger diameter. However, it is also possible to construct the flattened strands so that they comprise two layers of strand forming means having a uniform diameter in both layers.

As mentioned, the round filler strands 6 are of smaller dimension than the flattened strands 2 in order to fit into the spaces between adjacent flattened strands 2. This feature of the invention assures that the inner rope A has substantially a round cross section as well as a substantially smooth surface. Moreover, the shown arrangement of the filler strands in the spaces between adjacent flattened strands of the inner rope has the important advantage that the inner rope A has a larger metallic cross sectional area than the respective cross sectional areaof the outer rope. This is essential for assuring that the rope is torsion free. A rope is only then torsion free if the torsional moments resulting from the load in the individual layers of strands compensate each other. Since the leverage of the force effective on the outer layer is larger than the leverage of the force effective on the inner layer or rope, such compensation is possible only if the metallic cross sectional area of the inner rope is larger than the metallic cross sectional area of the outer layer. These conditions have been satisfied in a surprising manner by the present rope, especially by the use of said filler strands in the inner rope. These tiller strands 6 have preferably but not necessarily a metallic core wire 7. If desired, the filler strands may also have a fiber or synthetic material core.

The outer layer B of strands of a multi-strand rope according to the invention comprises either a plurality of round strands or it may also be made of flattened strands which would look similar to the flattened strands 2 except that the outer flattened strands would have but one layer of strand means surrounding a fiber or synthetic material core 8.

It is the special advantage of the invention that the present rope is non-rotating due to the fact that the inner rope has a larger metallic cross sectional area than the outer layer of strands.

FIG. 2 illustrates an embodiment similar to FIG. 1 except that in FIG. 2 the outer layer of strands also is made up of flattened strands 8, 9.

FIG. 3 illustrates a further embodiment wherein the smaller strands 6, 7 of the inner layer of strands have substantially the same diameter as the strands 8", 9" which form the outer strand layer.

Although a specific embodiment of the invention has been described it is to be understood that it is intended to cover all modifications and equivalents within the scope of the appended claims.

What I claim is:

l. A non-rotating rope having helical strands arranged in two layers of strands each layer of strands having a direction of lay opposite to that of the other layer of strands, comprising an outer layer of strands, an inner layer of strands, said outer layer of strands surrounding said inner layer of strands, and a center member of elastic material surrounded by said inner layer of strands, said inner layer of strands comprising three to six flattened strands each having its own elastic strand core and three to six strands of smaller dimension than that of said flattened strands.

2. The non-rotating rope according to claim 1, wherein said strands of smaller dimension are wire strands.

3. The non-rotating rope according to claim 1, wherein said outer layer of strands comprises a plurality of flattened strands.

4. The non-rotating rope according to claim 1, wherein said flattened strands of the inner layer of strands have spaces therebetween, said wire strands of smaller dimension being located in said spaces to substantially fill said spaces.

5. The non-rotating rope according to claim 4,

wherein said flattened strands and the strands of smaller dimension located in said spaces between adjacent flattened strands form an inner rope corresponding to said inner layer of strands, said inner rope having a substantially round cross section and a substantially smooth surface.

6. The non-rotating rope according to claim 5, wherein said flattened strands of said inner layer of strands comprise two layers of strand forming means arranged in equal lay fashion and surrounding the respective elastic strand core.

7. The non-rotating rope according to claim 6, wherein said elastic strand core is made of fiber material.

8. The non-rotating rope according to claim 6, wherein said elastic strand core is made of synthetic material.

9. The non-rotating rope according to claim 6, wherein said two layers of strand forming means comprise an inner layer and an outer layer of strand forming means, said strand forming means comprising elements of different diameter, said outer layer of strand forming means comprising elements of larger and smaller diameter whereby elements of larger diameter alternate with elements of smaller diameter.

l The non-rotating rope according to claim 1,

wherein said strands of smaller dimensions of said inner layer of strands and said strands forming said outer layer of strands have substantially the same diameter.

11-. The non-rotating rope according to claim 1, wherein the strands of said outer layer of strands include a core means.

12. The non-rotating rope according to claim 11, wherein said core means are made of fiber material.

13. The non-rotating rope according to claim 11, wherein said core means are made of synthetic material.

14. The non-rotating rope according to claim 1, wherein said outer layer of strands comprises sixteen strands. 

1. A non-rotating rope having helical strands arranged in two layers of strands each layer of strands having a direction of lay opposite to that of the other layer of strands, comprising an outer layer of strands, an inner layer of strands, said outer layer of strands surrounding said inner layer of strands, and a center member of elastic material surrounded by said inner layer of strands, said inner layer of strands comprising three to six flattened strands each having its own elastic strand core and three to six strands of smaller dimension than that of said flattened strands.
 2. The non-rotating rope according to claim 1, wherein said strands of smaller dimension are wire strands.
 3. The non-rotating rope according to claim 1, wherein said outer layer of strands comprises a plurality of flattened strands.
 4. The non-rotating rope according to claim 1, wherein said flattened strands of the inner layer of strands have spaces therebetween, said wire strands of smaller dimension being located in said spaces to substantially fill said spaces.
 5. The non-rotating rope according to claim 4, wherein said flattened strands and the strands of smaller dimension located in said spaces between adjacent flattened strands form an inner rope corresponding to said inner layer of strands, said inner rope having a substantially round cross section and a substantially smooth surface.
 6. The non-rotating rope according to claim 5, wherein said flattened strands of said inner layer of strands comprise two layers of strand forming means arranged in equal lay fashion and surrounding the respective elastic strand core.
 7. The non-rotating rope according to claim 6, wherein said elastic strand core is made of fiber material.
 8. The non-rotating rope according to claim 6, wherein said elastic strand core is made of synthetic material.
 9. The non-rotating rope according to claim 6, wherein said two layers of strand forming means comprise an inner layer and an outer layer of strand forming means, said strand forming means comprising elements of different diameter, said outer layer of strand forming means comprising elements of larger and smaller diameter whereby elements of larger diameter alternate with elements of smaller diameter.
 10. The non-rotating rope according to claim 1, wherein said strands of smaller dimensions of said inner layer of strands and said strands forming said outer layer of strands have substantially the same diameter.
 11. The non-rotating rope according to claim 1, wherein the strands of said outer layer of strands include a core means.
 12. The non-rotating rope according to claim 11, wherein said core means are made of fiber material.
 13. The non-rotating rope according to claim 11, wherein said core means are made of synthetic material.
 14. The non-rotating rope according to claim 1, wherein said outer layer of strands comprises sixteen strands. 